1. Field of the Invention
This invention relates to a system including an apparatus and method for the installation of well stimulation apparatus downhole utilizing a service tool string for gravel packing a downhole formation, and more particularly to such a system in which the tool string forms the production string for production of the downhole formation to provide a one trip gravel pack and production system.
2. Background of the Invention
Heretofore, it has been common to provide well stimulating apparatus for fracturing a formation in which the apparatus is lowered within a well bore on the lower end of a service tool on a work string. The stimulating apparatus for hydraulic fracturing with a proppant, such as a sand slurry, may include a lower perforating gun which is utilized for perforating the well casing at the production zone, and a production screen or filter is then positioned. After perforation of the well casing, a gravel packing packer assembly is lowered by a service tool to a position where the production screen is adjacent the production zone. The packers are then set and the proppant is injected into the fissures of the formation upon actuation of a crossover tool member to open a crossover port for flow of the proppant downwardly in the annulus between the tool and casing to the perforated casing for fracturing the formation to increase the size of the fissures receiving the slurry. After injection of the proppant or hydraulic slurry into the producing zone and the actuation of the crossover tool member to block further downward flow, the service tool may be disconnected from the gravel packing packer assembly and the service tool string removed from the well by a suitable rig. Then, a production tubing string is lowered into the well and connected to the gravel packing packer assembly adjacent the upper packer for the production of a hydrocarbon fluid from the producing zone. The production tubing string is supported from a wellhead.
Such a process is time consuming and requires a rig for running in the production string and for removing the work string after the fracturing process has been completed. A single trip for a work string to provide perforation and sand control has commonly been used heretofore but the installation of production tubing has normally required a separate trip after the work string has been removed.
However, U.S. Pat. No. 5,174,379 dated Dec. 29, 1992 shows a sand packing system in which the well is perforated, gravel packed, and placed on production with a single trip of the tool string into the well. The system includes a crossover assembly having a closure mechanism operated to preclude downward fluid flow through the tool, to establish a downward slurry flow path, and to establish a carrier fluid return flow path. At the end of the gravel pack operation, the tool string is placed on production without tripping the tool string.
The '379 patent includes a crossover assembly that is effective to provide a first flow path from the interior of the tubing string at a location above the packer to the wellbore annulus below the packer, and is selectively operable to provide a second flow path from the interior of the tool string below the packer to the annulus in the wellbore above the packer. The operating mechanism associated with the crossover assembly includes a probe or dart assembly which is lowered into the well after the crossover assembly is in the well. A wireline is normally utilized for removal of the probe.